Holocaust scholars are arguing over whether a memorial in Berlin should include lesbians.

The memorial consists of a concrete slab with a window where viewers can see a continuous film of two men kissing.

Between 5,000 and 15,000 gay men were estimated to have been interred in concentration camps during the Nazi rule of Germany. They were targeted alongside Jews, gipsies, Jehovah’s Witnesses and political dissidents.

When the memorial was opened in 2008, it was agreed that the video would be switched every two years to represent both lesbians and gay men, after lobbying from lesbian groups.

The video is due to be changed to show two women kissing in May.

However, Holocaust scholars argue that lesbians were not targeted during the atrocities and that including them in the memorial would “distort history”.

Alexander Zinn, a board member of the foundation that maintains the former Nazi concentration camps near Berlin, told AFP: “It’s a distortion of history as there were no known Holocaust victims targeted for being lesbian and historical truth must remain focused.”

He and other experts have written a letter of protest to culture minister Michael Neumann and Berlin’s openly gay mayor, Klaus Wowereit.

Mr Neumann defended the decision to switch the film to lesbians kissing.

He said in a statement: “The option of using a lesbian film motif in the memorial is in no way meant to put on the same level the persecution of homosexual men and women under the Nazi regime.

“Research shows that the persecution of lesbian women by the Nazi regime was not comparable to that of homosexual men. This is also clearly explained in a plaque on the memorial.”

The Nazis believed that gay men were weak and could not help defend Germany or increase its birthrate. Therefore, they were seen as threat to Nazi racial policies.

Some were experimented on to find a “cure” for homosexuality, suffering mutilation and death.

Although lesbians bars were closed and some lesbians were arrested for being prostitutes, they were not subjected to systematic persecution in the same way.